Having an electrician over this week.....
 

With all the power cable/receptacle talk on here the last few days, figured I'd get some feedback. I'm having an electrician over at the house this week for a couple of minor projects not related to audio/video. I figured that since he was here I might have him take a look at the job the original electrician did when we built our house. He ran two dedicated 20 amp lines to my room, one line for the preamp/digital/analog setup and the second line for the power amplifier between the two speakers. I've never had any noise or hum issues, and to my knowledge, everything seems to work just fine but obviously it wasn't an upgrade so I have nothing to compare it to.

My question is whether or not I should get an estimate for a couple of things I've read online. Are runs of 10 gauge instead of the standard 12 really audibly different? Would it be beneficial to move the system to a subpanel and have that be only for the audio system?

Is there anything else you guys can think of that I could have him take a look at while he's here that could give me a positive benefit?

- Buck

Having two dedicated 20 amp lines is good enough in my book. That's what I did back in the day when I built my house. I doubt any further expense of a sub panel or going 10 vs 12 gauge will yield any noticeable results what so ever. You could use that money to buy a nice power conditioner if you don't already have one, if you really want to clean up the power.

Having an electrician over this week.....
 

Hey Buck

If he’s there have him just do a look over making sure all connections are tight to the breaker. Maybe consider changing the outlets (Ivan had listed Furutechs, not sure if he still has them) if that’s something you can’t do, otherwise, you should be set as you stand and listen. Hope your well!

That was my other thought as well. Shunyata Denali anyone?:banana: I'd be replacing a Hydra 4 but with everything I've read the Denali seems to be the top of the mountain.

- Buck

Can't help you with your Shunyata question, never owned their products but your MC402 is as happy as it will ever be on that dedicated 20 amp line. :D

Buck.......If your 20 amp circuits with #12 copper are 50' or less there is nothing to be gained by going to #10 copper wire. The reason you move to larger gauge wire is to offset a voltage drop or to enable higher current. You are using 20 amp circuit breakers for each of your two dedicated circuits so #12 copper meets the NEC code requirement for the 20A overcurrent protection.

For the sake of discussion lets assume your total circuit lengths from breaker to receptacles are 50'. Using a voltage drop calculation for the load (amps), the wire length (50'), the voltage (120 V), and the wire size (#12 CU), a full 20 amp load on #12 copper wire at 50' will have a voltage drop of 3.4 volts. You are unlikely to ever have a full 20 amp load on either of your dedicated circuits.

Your MC402 amplifier is rated at a maximum current draw of 10 amps at 120 volts. The amplifier is unlikely to ever draw more than 5 amps with music playing extremely load.
Even then a 5 amp load is not continuous since the current draw from the dedicated circuit mirrors the amplifier's output, and we know music has peaks and valleys that cause the amplifier's output to rise and fall right along with the amplifier's current demand.

I calculated a voltage drop for a 10 amp load with #12 copper at 50' and get 1.7 volts drop. The voltage drop for a 5 amp load with the same wire and distance is 0.8 volt.

Your source components, preamplifier and phono preamplifier combined loads are less than 4 amps total. That represents a voltage drop of 0.7 volt with #12 wire at 50' length.

Your MC402's typical maximum current draw will be about 5 amps. That is 0.8 volt drop from the 120 volt dedicated circuit with #12 wire at 50' length.

For comparison the voltage drop for #10 copper wire at 50' with a load of 5 amps is 0.5 volt. The voltage drop for #10 copper wire at 50' with a load of 10 amps is 1.1 volts. The voltage drop for #10 copper wire at 50' with a load of 20 amps is 2.1 volts.

So there you have it. Using the information provided it is easy to see there is little gain of any real value to your sound system by going to #10 copper wire over #12 copper wire when the circuit length is 50' or less. The shorter the distance of a dedicated circuit, the smaller the voltage drop.

All things considered you could quite easily power your whole sound system from a single 120 volt, 20 amp dedicated circuit with a realistic load of approximately 9 amps. The voltage drop for a 9 amp load over 50' with #12 copper wire is 1.5 volts. The majority of audio components can safely be operated at +/- 5 volts AC from their stated requirements without issue, so you can see that the minor voltage drops outlined above on a #12 copper wire circuit of less than 50' is not an issue.

Does any of this stop us crazy audiophiles from installing #10 wire for our dedicated circuits? Probably not. #10 copper wire certainly won't jeopardize the circuit's integrity or safety. It does make it more difficult to terminate the wire to 20 amp rated wall receptacles designed to accept #12 wire, but it isn't impossible. I recommend people install the correct wire size for the overcurrent protection (circuit breaker) as required by the National Electrical Code. To exceed the NEC requirements is not a crime, so make yourself happy if you decide to go that route.

Thanks Dan, that's above and beyond the call of duty.....I appreciate the detailed info!

- Buck

There you have it, leave it to Dan to break things down in a logical, rational and educational manner. :thumbsup: Thanks for that informative post Dan. :yes:

Mike approved!

https://memegenerator.net/img/instan...-yesth-you.jpg

I would suggest checking if both lines are on the same phase in your main box. The simplest way to do that is to look at your panel, if the breakers are one below the other they are on opposite phases (not good). If they are right/left, or skip one on the same side they are on the same phase (good).

CAUTION THIS METHOD SHOULD BE DONE BY QUALIFIED PERSONELL.

You can also use an AC volt meter, measure between both neutrals or hots (between both circuits) If it reads more than one or two volts it's out of phase.

I have two separate dedicated lines and my system sounds better when plugged into one line. My best guess (reason) for this is the proximity (nearness) of the ground connections for each component.

You now have centralized from one outlet your power distribution & I speculate there could have been, when using more than one dedicated outlet, a conflict of both signal and ground paths which created "noise".

By going to the one dedicated, you eliminated that conflict.

I myself have reverted to one dedicated 20A outlet to power all my gear & run it thru not a power conditioner (which IMO impedes the power line and compresses dynamic range of the music), but a power distribution bar with a high quality AC cable from the 20A dedicated receptacle. This approach and device addresses AC Mains contamination, EMF/RF interference and that conflicting flow of signal and ground paths via a low impedance star ground.

Best Sir,

Bob

One more question for Dan or any others more knowledgable than me about this........the dedicated line to my amplifier is run to a standard duplex outlet. I think I may get him to install a second for future considerations in case I were to add anything up front, go to monoblocks etc..... Will he have to run another line to the duplex outlet or do you just piggyback it to the line already there, in essence turning it into a quad receptacle?

- Buck

Interesting ......... for I did my best to relocate my 'noise' generating devices (dimmers, appliances, misc rheostat switches, etc) to one down leg and my audio (2 dedicated 20amp, 10ga) lines to the other. FWIW, a friend of mine (electrician) recommended this ? no ground loop or other artifact issues that I can tell

Dan, BTW, good post (#6) ....... :thumbsup:

Buck.......A dedicated circuit can easily be shared with a second duplex receptacle, although it is typical for a dedicated circuit to have a single duplex receptacle. The important thing to keep in mind, don't share this additional receptacle with electrical loads that are not part of the audio system. Also make sure you are using quality receptacles, not contractor grade outlets. Hubbell, Leviton, and Pass & Seymour hospital grade receptacles have certified clamping pressure that resists plugs from accidentally becoming disconnected. This extra clamping pressure ensures a firm secure electrical connection.